For the third year in a row, every senior at Urban Prep Academy, the only all-African-American, all-male charter high school in Chicago, has been accepted to college, the school's leaders said.

The academy also said that 83 percent of its first graduating class in 2010 has re-enrolled in a second year of college, a rebuttal to critics of the school who have charged that students aren't always ready for college.

Critics have also suggested that Urban Prep squeezes out students with academic and discipline problems who other schools have to work with. Urban Prep officials acknowledge that this year's senior class of 85 was almost twice that size when the boys started out as freshmen.

But Urban Prep CEO Tim King, in a meeting Thursday with the Tribune's editorial board, vigorously denied that troubled students are forced out or encouraged to leave.

"We take the opposite view," King said. "We devote time and energy to those students so that they understand they can do well and they can have success if they modify their behavior."

King will announce this year's perfect college rate at an assembly at Urban Prep's Englewood campus Friday morning.

Urban Prep's success in making college a reality for African-American children from tough, low-income neighborhoods has won national attention. Last year's graduation rate for African-American males in Chicago Public Schools was 44 percent. About half of those who graduate enroll in college, according to CPS.

Julie Woestehoff, executive director of Parents United for Responsible Education and a leading critic of charter schools, said the perfect college acceptance rate at Urban Prep is not showing a true picture of what is taking place in the school.

"The aura of 100 percent is just a cover for what is a fairly typical Chicago public high school where about half the kids don't graduate," Woestehoff said. "They may say they're not forcing or encouraging kids to leave, but what is happening? The public has the right to know, especially when they present themselves as a miracle. This is not a miracle."

Urban Prep spends about $12,000 per pupil — far more than a typical CPS school. Once students graduate, the school stays in touch with them. A rigorous alumni department brings students in over the summer to familiarize them with the challenges ahead and continues to contact graduates twice a month by phone, email or on Facebook.